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activoice

join:2008-02-10
York, ON

Redirect outbound to different port

Trying to help a friend out here...

He's got software on his Windows PC that has an e-mail feature.

The problem with this email feature is that it has been hard coded to use port 25 (yeah I know, poor design). As most ISP's block port 25 traffic going anywhere but their own e-mail server I was wondering if there is a program for Windows that will take outgoing port 25 traffic and redirect it to port 465 for example.

(I've seen programs that redirect incoming traffic, but can't seem to find anything that redirects outgoing traffic)

Any ideas?



PToN
Premium
join:2001-10-04
Houston, TX

Your Network Admin should easily be able to do this using NAT. Basically you would setup a rule like: src=HOST-IP sport=25 dst=ANY or 0.0.0.0/0 dport=465


activoice

join:2008-02-10
York, ON
reply to activoice

If this was a corporation I would agree with you. But it's my friend's home business... he has no system administrator..

So since this program only runs on the one Windows PC, I was wondering if there is a solution that can be run on the PC to take care of this routing.



exocet_cm
Free at last, free at last
Premium
join:2003-03-23
New Orleans, LA
kudos:3

said by activoice:

If this was a corporation I would agree with you. But it's my friend's home business... he has no system administrator..

So since this program only runs on the one Windows PC, I was wondering if there is a solution that can be run on the PC to take care of this routing.

You might be able to setup a mail relay on the local host. His program would send mail outgoing on port 25 to 127.0.0.1. The local host would run a mail relay server using IIS which would then relay the outgoing mail to an external mail server running SSL/TLS.

We do this at work. Often times certain network hardware will only use port 25 and nothing else. We relay this mail to an internal IIS relay server and then forward it to Google's mail servers.

Matter of fact, I had a thread a few weeks ago in asking how to round-robin SMTP relay servers. PToN See Profile, DarkLogix See Profile, and others were helpful in the matter.
--
"I have measured out my life with coffee spoons..." - T.S Eliot
"I have often regretted my speech, never my silence." - Publilius Syrus
Ma blog: »www.johndball.com


PToN
Premium
join:2001-10-04
Houston, TX
reply to activoice

Most home routers are capable of doing NAT on outgoing traffic. I know that my old linksys can. If you can get the model of his home router, it would help some people here give you some answers.


activoice

join:2008-02-10
York, ON
reply to activoice

Thanks... I'll look at those...

I was hoping there would be some simple solution.. I have a hard time believing that the vendor for the software he is using hard coded port 25 and didn't make it user configurable, the software license costs thousands of dollars... can't believe they missed something so simple.


HELLFIRE
Premium
join:2009-11-25
kudos:18
reply to activoice

You may want to read up on TCP / UDP ports 1 - 1024, they're called REGISTERED ports for a reason. It doesn't date back
to a coder being lazy and not allowing you to set your port(s) accordingly for SMTP, it dates back to when the original RFC
was written back in 1982 here.

The SMTP transmission channel is a TCP connection established
between the sender process port U and the receiver process port
L. This single full duplex connection is used as the
transmission channel. This protocol is assigned the service
port 25
(31 octal), that is L=25.

I second PToN's suggestion of redirecting it via NAT on the router if possible, as that's the least painful way I can think
of to do this.

Otherwise your friend will have to sit down with his ISP or a hosted email provider to come up with another solution.

Regards


exocet_cm
Free at last, free at last
Premium
join:2003-03-23
New Orleans, LA
kudos:3
reply to activoice

said by activoice:

Trying to help a friend out here...

He's got software on his Windows PC that has an e-mail feature.

The problem with this email feature is that it has been hard coded to use port 25 (yeah I know, poor design). As most ISP's block port 25 traffic going anywhere but their own e-mail server I was wondering if there is a program for Windows that will take outgoing port 25 traffic and redirect it to port 465 for example.

(I've seen programs that redirect incoming traffic, but can't seem to find anything that redirects outgoing traffic)

Any ideas?

Any luck with finding a solution?
--
"I have measured out my life with coffee spoons..." - T.S Eliot
"I have often regretted my speech, never my silence." - Publilius Syrus
Ma blog: »www.johndball.com

activoice

join:2008-02-10
York, ON
reply to activoice

I left it with my friend to discuss with the company that setup his network... he's paying them for support I guess they should expend some effort to figure it out.



workablob

join:2004-06-09
Houston, TX
kudos:3
Reviews:
·Comcast
reply to exocet_cm

Agreed. OP could setup SMTP in IIS to use a SmartHost pointing to your ISP SMTP servers on port 587.

I do this on my mail server at home since a lot of orgs will reject mail from a DHCP client.

Dave
--
I may have been born yesterday. But it wasn't at night.